View
218
Download
0
Category
Preview:
Citation preview
6/10/2011
1
Nondestructive Quality Measurement of Horticultural Crops
David Slaughter
Biological & Agricultural Engineering
UC Davis
Additional information available at:
Technologies for Nondestructive Quality Evaluation of Fruits and Vegetables.
Abbott J.A. et al., Horticultural Reviews Vol. 20, 1997.
Quality measurements
Many quality measurement techniques have been developed to mimic the human senses sight, smell, sound, touch and taste
Others are measures of harvest, storage, and handling characteristics that affect quality. Bruise susceptibility
Non-destructive measurements allow 100% sampling Allows sorting into uniform subunits, removal of
substandard items, and identification of premium pieces.
Non-destructive measurements also allow monitoring of quality over time.
Quality measurements
External Properties Size & Shape
Mass, Volume & Density
Appearance, Color &
Visible Blemishes
Composition, Flavor & Aroma
Texture, Firmness, Crispness, Mealiness
Internal Defects, Decay, Insect Damage
Internal PropertiesNon-destructive technologies for fruit and vegetable size determination – a review
G.P. Moreda, J. Ortiz-Cañavate, F.J. García-Ramos, M. Ruiz-Altisent. 2009.
Journal of Food Engineering 92 :119–136
Machine Vision On-line vision systems
examine multiple views of each fruit as they travel on a conveyor. Provide measures of
size shape and volume
4 imagesscanned at eachlocation
size, shape and volume.
External blemishes can be detected with a high degree of reliability.
When combined with fruit weight, the density can be an indicator of internal quality.
Fruit rotates as it travels to expose all sides
Traditionally a Destructive Method
Magness-Taylor Penetrometer
Invented in 1925 Invented in 1925.
Records the Maximum Force Required to Penetrate the Fruit.
Manually Operated.
Penetrometer
Fruit Firmness Methods
Destructive Maximum Force to
Penetrate a Known Distance into Fruit.
ce
FMAX
Measures tissue t th
Deformation
For
c
Non-Destructive Force Required to
“Squeeze” Fruit.
Measure of elastic tissue properties.
strength.
6/10/2011
2
Durometer Portable instrument used to
determine the ‘Shore A’ hardness of rubber.
Handheld (or stand mounted).
Use 5mm wide ‘E’ tip for peaches or pears.p p
Uses a calibrated spring to measure the resistance to deformation.
Will bruise soft fruit.
$800 - $1200
A durometer consists of:
Principle of Operation
0 percent
40
CalibratedSpring
A calibrated spring,
A tip displacement gage, and
A retractable tip
Pear
0 100
Tip extends2.5 mm
Principle of Operation
0 percent
40
DurometerDisplays
100 percent
40
Pear
0 100 0 100
Pear
Tip extends0.1 inches
A very hard pear can press 100% of the tip into the probe
Principle of Operation
0 percent
40 40
40 percent100 percent
40
Pear
0 100
Pear
0 1000 100
Pear
A softer pear can only press the tip partially into the probe
Bartlett Pear
y = 0.5525x - 2.5
r2 = 0.77
40
45
50
55
ss (
Sin
clai
r) R2 = 0.77
Durometer measurement of Bartlett Pears
20
25
30
35
40 50 60 70 80 90 100
'E' Durometer (%)
Imp
act
Fir
mn
es
Durometer measurement of Bartlett Pears
80
90
100
Sco
re
logarithmic regression using all data:y = 14.174Ln(x) + 47.45, R2 = 0.9028
40
50
60
70
0 5 10 15 20 25
Penetrometer Firmness (lbs)
linear regression using penetrometer firmness > 10lbs:y=0.99(x) + 70.7, R2=0.50
Du
rom
eter
S
6/10/2011
3
Low-mass impact methods are widely available for measuring firmness on-line. Spherical tip gently taps the fruit
Accelerometer on impacting arm senses tissue elasticity
Principle of Operation
A
Firmness Index
t
A
PeaktoTime
onAcceleratiPeakC
t
Principle of Operation
AFirmness Index
AonAcceleratiPeakC
t
A
t
tPeaktoTimeC
Monitoring Impact FirmnessDuring Ripening of Mango
ratio
n
CDay1=275
Source: I. ShmulevichSource: I. Shmulevich
time
acce
le
CDay7=65
UC Davis handheld nondestructive firmness sensor for orchard use.
Sinclair Nondestructive firmness tester. “Gently” taps the fruit and provides a Sinclair iQ firmness
value.
OnlineModel
Bench Top model
6/10/2011
4
Clingstone Peaches
Comparison of Penetrometer Firmness vs Impact Firmness
R2 = 0.6
Acoustic Firmness Measurement Aweta/Autoline on-line acoustic firmness sensor
“Gently” taps fruit and “listens” with a microphone.
Uses Fourier analysis to determine the natural frequency of the fruit.
Firmness = f2 * m2/3
Bench top
On-line model
Bench top model
Acoustic Firmness Principle
Natural frequency and firmness Acoustic Firmness =f2 m2/3
where :f - first resonant frequencyq y
m - fruit’s mass.
Acoustic Firmness sensor
10000
3
22 mf
S
Acoustic Firmness sensor
Good
Acoustic impact can also detect internal cavities in melons.
Hollow
B. Diezma-Iglesias, M. Ruiz-Altisent, & P. Barreiro. 2004
NondestructiveOn-line Firmness sensor
AWETA online firmness sensor Acoustic & Impact
sensors
6/10/2011
5
Impact vs. Acoustic Firmness
Acoustic Method Global
Measurement Resonance of
Impact Method Local spot
measurement Elastic properties of
fwhole fruit is measured.
Some internal defects can be sensed
Works better on firm fruit
exterior flesh is measured.
Cannot sense internal defects
Works better on soft fruit
Automatic Fruit QualityGrading in Cherry
Stem Width
FirmnessFruit WidthColor
Pulp Temperature
Optical Firmness Principle
Researchers are attempting to develop light scattering models to predict firmness.
Yankun Peng, Renfu Lu. 2007. Journal of Food Engineering 82:142–152
Volatile Sensing
Electronic nose 32 co-polymer sensors
Classify volatiles using artificial neural network.
Detecting freeze damage in oranges
32 co-polymer sensors
Headspace Ethanol measurement for Freeze Damage Oranges are placed in one quart plastic bags.
Ethanol predicts freeze damage with 80% to 90% accuracy in 7 fruit batches.
Slightly damaged (<15%) fruit are not detected.
• VolatilesVolatiles accumulate for 1/2 hr at room temp. (Not suited for on-line use.)
• $800 Etoh
Sensor.
Electromagnetic Spectrum
X-RAY
ULTRA-VIOLET
INFRAREDRADIOWAVE
MICROWAVE
FREQUENCY (Hz)NIR
VISIBLE
108 109 1010 1011 1012 1013 1014 1015 1016 1017
1010 109 108 107 106 105 104 103 102 10 1
WAVELENGTH (nm)
6/10/2011
6
Material/Light Interactions
Light interacts with produce in 3 ways: Reflectance, Transmittance, and Absorption
L*, a*, b* color system Color can be used in
many crops as an index of maturity or ripeness.
Instruments to measure the peel color of fruits and vegetables are gavailable from several manufacturers.
L* represents luminous intensity
a* represents the red - green content
b* represents the blue - yellow content
a* b* Chromaticity Diagram
a*= red to green axis
b*= yellow to blue axis
Hue = name of color (e.g., yellow, green)
Measured in degrees Measured in degrees
Clingstone Peach Maturity
45
90
80
Gardner ‘a’ value or CIE hue angle have been demonstrated to be good indices of clingstone peach maturity.
Peaches with a flesh
CIE hue angle
0
270
180
Peaches with a flesh hue angle below 80 degrees are mature
Infrared Spectroscopy
All organic and inorganic molecules, except homonuclear molecules (e.g., O2), absorb light in the infrared region.
The light absorptions in the infrared typically cause vibrations in a molecule.
C = LOG10[1 / T]L
• Beer-Lambert Law
SymmeticStretch
In-planeScissoring
• Allows optical measurements of chemical constituents in the sample.
Absorbance Spectra Below is a picture of a cup of water
What color would the water appear in the infrared?
Black
6/10/2011
7
Absorbance Spectra NIR Applications in Food
Moisture Grains, Forages, Fruits,
Meat, Milk, Cheese, Seeds, Soil.
Protein Grains, Forages, Meat,
S d
Carbohydrates Grains, Breakfast
Cereals, Seeds.
Starch Grains, Seeds, Kiwifruit.
FiberSeeds.
Soil Nitrogen Ethanol Beer, Wine.
Fat Oil seeds, Milk, Meat,
Cheese, Snack Foods, Human Triceps.
Grains, Forages.
Amino Acids Grains
Defects Bruising, Contaminants.
On-line Near Infrared (NIR) Measurements
High light source power (150 - 300 Watts) allows transmission measurement of intact citrus in the NIR. NIR On-line
Sugar sensor
Miller & Zude−Sasse (2004)
NIR on-line testred grapefruit (20 oC)
On-line NIR Evaluation Study
Miller & Zude−Sasse (2004) Evaluated on-line NIR SSC sorter (Mitsui Qscope) 5.5 fruit/second belt speed Red & white grapefruit were studied
Results: Fruit temperature during sorting must match
temperature during calibration. Measurements on smaller fruit were more accurate
than on larger fruit.
Brix Sorting Test Results (2 categories)
Classification accuracy: 79% (76% - 100%)
6/10/2011
8
NIR Applications Recently some
commercial, handheld NIR instruments have become available.
Experience at UC Davis: “closed” type instruments are
calibrated at the factory andcalibrated at the factory, and the calibration has not performed well in California.
Good success obtained with “open” type instruments, which allow on-site calibration. NIRVANA
SACMI
Nondestructive measurement of fruit and vegetable quality by means of NIR spectroscopy: A reviewPostharvest Biology and Technology 46 (2007) 99–118Nicolai, B.M, K. Beullens, E. Bobelyn, A. Peirs, W. Saeys, K.I. Theron, J. Lammertyn
New commercial handheld instruments have been recently developed for measurement of i l li h
Handheld Instrument for Nondestructive Determination of Internal Quality
internal quality parameters such as oBrix.
• One instrument, called the NIRVana, shows particular promise because it is an “open” instrument, which allows model optimization for local cultivars and production practices.
Identification of Immature Green Tomatoes at the Time of Harvest
Immature
Tomato Spectrum
Results
Results show that the handheld instrument can correctly identify 70% of immature tomatoes.
Measurement of Fresh Fruit Spectrum using ‘Nirvana’ Spectrometer
6/10/2011
9
Peach Spectrum (Flesh Color)Results
Measurement of Soluble Solids in Peaches
Measurement of Flesh Color in Peaches
Results
External Validation of Developed Spectral Model with ‘Loadel’ Peach Variety
Results
Measurement of Internal Quality (Soluble Solids) of Mandarins
Measurement of Internal Quality (BrimA score) of Mandarins
6/10/2011
10
Fluorescence Some molecules can
re-release absorbed optical energy as a lower energy photon.
http://probes.invitrogen.com
(vibration or heat)
Example: Using citrus peel oil fluorescence to determine fruit quality
Tangeretin a nonvolatile, neutral flavone.
fluoresces an orange color under long wave UV (S ift 1967)wave UV (Swift, 1967).
High levels in peel oil of orange, grapefruit and some tangerines, low levels in lemon (Manthey & Grohmann, 2001).
Events that cause peel oil release can be detected using UV fluorescence.
Peel Oil under Blacklight
grapefruitlemon
grapefruitlemon
lime
orange
lime
orange
tangerine
Viewed under blacklight
tangerine
Low level off d
Freeze Damaged Oranges Fluoresce
Relationship to flesh damage Varies with both freezing &
thawing conditions.
freeze damage
Moderate to severe freeze
damage
• Agreement between the USDA and UV methods ranged from 35% to 85% in lab. and field studies in 2006 & 2007
Thrip Damage
Thrip damage is also visible under blacklight
Fluorescence due to extensive thrip damage Blasco et al. (2007)
Appearance of decay lesions under UV light
Note that the infected lemon does not fluoresce
Smilanick, 2008
6/10/2011
11
75
50
Initial
After 3 weeks
%
Quality (% choice or higher) of navel oranges Initially and After 3 weeks storage at 60F
0 2 31
25
0
%
Fluorescence classNONE VERY HIGH
GoodFruit
Smilanick2008
Grove Inspection using UV flashlights
Fecal Contamination Fluorescence
Fruit surfaces contaminated with fecal matter can be detected with UV fluorescence.
Dilute fecal matter was applied in a grid pattern
Fluorescence Images
Moon S. Kim, Alan M. Lefcourt, Yud-Ren Chen, Yang Tao. 2005
Nuclear Magnetic Resonance (NMR)
Hydrogen atoms in a biological material act like magnetic dipoles
N
Proton
MagneticDipole
Hydrogen
magnetic dipoles due to the rotation of the electron around the proton. S
Electron
Nuclear Magnetic Resonance (NMR)
Under normal conditions the magnetic dipoles point in random directions.
Nuclear Magnetic Resonance (NMR)
The material is placed inside a powerful electro-electro-magnet.
This causes the dipoles to align with the magnetic field.
6/10/2011
12
Nuclear Magnetic Resonance (NMR)
A radio frequency (RF) pulse is then used to “knock” the atoms out of alignment.
Nuclear Magnetic Resonance
When the RF pulse stops, the atoms spiral back into alignment with the magnetic field.
The time it takes for realignment is called gthe relaxation time (usually within milliseconds).
The realignment process creates its own radio frequency signal that is detected by the system.
NMR measurement of Avocado Quality
NMR - Data Analysis
NMR - Example Applications
Seed/pit detection
Worm damage
Bruises
Water core
Magnetic Resonant Image of Partially
Frozen Orange
Freeze damage
Freeze Damaged Tissue
Healthy Tissue
Portable MR System
Magnet
Permanent magnet NMR sensor(Quantum Magnetics Corporation, San Diego,CA)
ElectronicsFruit
6/10/2011
13
Behavior of non-metallic materials when placed inside an alternating electric field. Moisture of dates and other “dry” fruits or nuts.
Dielectric measurements
Metal Plate + Positive Charge +
Before Energizing
Metal Plate
Dielectric Material
- Negative Charge -
+ +
-
+ +
-
+ +
-
+ +
-
+ +
-
+ +
-
After Energizing
Dielectric Moisture Meter
Empty Walnut Drying Bin Bin Sides are a Capacitor with Walnuts as the Dielectric Material
X-Ray & Gamma-Ray
Maturity of lettuce heads
Defect detection Freeze damage in citrus -
online
Olive, showing fruit fly entrance hole
Split pits in peach
Hollow heart in potato -online
Bruises in apple
X-ray image showing tunnels.
R. Haff
Recommended